* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *This jobbing-size Campbell "Complete" of the 1870s displays all the characteristics of the Campbell single revolution Country press introduced in 1861, plus a few add-ons for the job printer, such as the geared vibrator driving the form rollers. There are no bed tracks; the bed rides on pulleys attached to the side frames. Rollers mounted on the impression girder under the cylinder support the bed during the impression. Campbell's unique (and patented) bed-drive involved driving the bed from gear segments on the massive bull-wheel attached to the cylinder shaft. A cross-shaft under the bed carries a pinion at its center driving a rack on the bed's underside. The shaft reverses to reverse the bed. A pinion on the off-side end of the cross-shaft engages the gear segments on the bull wheel. The inner segment drives the bed on the printing stroke, the outer segment returns the bed at an increased velocity, thus evening the power required to drive the machine and allowing a small-diameter cylinder. Two sets of grooved cams on the bull-wheel (one set is out of sight in this cut) engage studs on the face of the pinion on the off-side end of the cross-shaft to stop and reverse the rotation of the shaft at each end of the bed stroke. The near-side end of the cross-shaft carries the gearing and worm to operate the form-roller vibrator, and a pulley for the leather strap that operates the fountain. The front-guide shaft runs in vee-blocks, rather than plain bushings, to obviate mis-register from wear at this point--another patented feature. The high "draught" of the power shaft, with its flywheel and tight-and-loose pulleys, was convenient for the turner when the press was hand-operated. The artist of our illustration has taken a bit of license, showing the bull-wheel in the wrong position relative to the cylinder. It has been depicted about 45 degrees too far clockwise and, as shown, would reverse the bed while the sheet was in the impression nip!

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Many thanks to good friend, Doug Charles [or "Mr. Flat Surface"] for this informative article. Doug's passion is the 'bed and platen' era, (see index), -- letterpress printing is in his blood, infused through a long association with Alaskan job and newspaper printing.